In a Universal Mobile Telecommunication System (UMTS), a device with an established packet data protocol (PDP) context, such as an always-on device, may be transitioned by a network to a CELL_PCH or URA_PCH state after a voice call ends or due to data inactivity during a packet data session, rather than be transitioned to an IDLE mode. This transition process keeps the mobile device in connected mode without any radio resources assigned and provides for faster connection establishment and less network signaling for the subsequent call.
In a CELL_PCH or URA_PCH state the use equipment (UE) uses discontinuous reception (DRX) to monitor broadcast messages and pages via a paging indicator channel (PICH) and performs cell update or URA update as needed.
In various network communications, when a UE is in the CELL_PCH or URA_PCH state, or in some cases even when the device is in a CELL_FACH state, if a circuit switched voice call is received for the device or originates from the device, the network may not perform fast transition of the device to a CELL_DCH state. Instead, the network may initially move or keep the device in CELL_FACH state during exchange of signaling messages until a radio bearer is established. This results in call establishment being performed over a common, low-rate physical channel, leading to increased latency for call setup. Further, in the case where the UE is at a boundary area and the transition of the device from one cell to another is required, due to the fact that soft or softer handover is not possible in CELL_FACH state the call setup may fail in some situations.